2,690 research outputs found
Genetic variability of muscle biological characteristics of young Limousin bulls
Genetic parameters of 4 muscle biological characteristics (protein to DNA ratio (Pro/DNA), lactate dehydrogenase (LDH) activity, isocitrate dehydrogenase (ICDH) activity and the proportion of type I myosin heavy chains (MHC I)), in the Semitendinosus and the Longissimus thoracis, were estimated simultaneously with average daily gain (ADG), 480-d final weight (FW), carcass lean and fat contents (CL% and CF% respectively) in a sample of young Limousin bulls tested in station. The data came from 144 animals, the progeny of 15 sires. Sire and residual variances and covariances were estimated u using an expectation maximization restricted maximum likelihood (EM-REML) procedure applied to a multitrait mixed model. Heritability coefficients of production traits, ADG, FW, CL% and CF%, were 0.19, 0.49, 0.39 and 0.43, respectively, while heritability coefficients of muscle characteristics, Pro/DNA, LDH, ICDH and MHC I, were 0.11, 0.26, 1.03 and 0.35 respectively, in the Semitendinosus muscle and 0.29, 0.31, 0.28 and 0.41, respectively, in the Longissimus thoracis muscle. In both muscles, the oxidative activity of the ICDH appeared to be genetically associated with the proportion of type I myosin heavy chains and opposed to the glycolytic activity of the LDH. The LDH activity was clearly associated with higher muscle-to-fat ratio, while the opposite relationship was observed between that ratio and the ICDH activity or the MHC I proportion.Les paramĂštres gĂ©nĂ©tiques de 4 caractĂ©ristiques biologiques - le rapport protĂ©ines /ADN (Pro/DNA), les activitĂ©s de la lactate dĂ©shydrogĂ©nase (LDH) et de lâisocitrate dĂ©shydrogĂ©nase (ICDH) et la proportion en chaĂźnes lourdes de myosine lente (MHC I) - des muscles Semitendinosus et Longissimus thoracis, et ceux du gain moyen quotidien (ADG), du poids vif finaL Ă 480 j (FW) et des teneurs de la carcasse en muscles et en dĂ©pĂŽts adipeux (CL% and CF% respectivement), ont Ă©tĂ© estimĂ©s simultanĂ©ment Ă partir dâun Ă©chantillon de taurillons Limousins contrĂŽlĂ©s en station. Le fichier comprenait 144 veaux issus de 15 pĂšres testĂ©s sur descendance. Les variances et covariances paternelles et rĂ©siduelles ont Ă©tĂ© estimĂ©es par la mĂ©thode du maximum de vraisemblance restreinte, avec lâalgorithme dâespĂ©rance-maximisation, appliquĂ©e Ă un modĂšle mixte multicaractĂšre (EM-REML). Les coefficients dâhĂ©ritabilitĂ© des variables de production, ADG, FW, CL% et CF%, sâĂ©levaient respectivement Ă 0,19, 0,49, 0,39 et 0,43, tandis que les coefficients dâhĂ©ritabilitĂ© des caractĂ©ristiques musculaires, Pro/DNA, LDH, ICDH et MHC I, valaient respectivement 0,11, 0,26, 1,03 et 0,35 dans le muscle Semitendinosus et 0,29, 0,31, 0,28 et 0,41 dans le muscle Longissimus thoracis. Dans les 2 muscles, lâactivitĂ© oxidative de lâICDH Ă©tait gĂ©nĂ©tiquement associĂ©e Ă la proportion de myosine lente et opposĂ©e Ă lâactivitĂ© glycolytique du LDH. Cette activitĂ© du LDH Ă©tait positivement corrĂ©lĂ©e avec le rapport muscles / dĂ©pĂŽts adipeux, alors quâune relation inverse Ă©tait observĂ©e avec lâactivitĂ© de lâICDH et la proportion de MHC I
The Role of Mesotocin on Social Bonding in Pinyon Jays
The neuropeptide oxytocin influences mammalian social bonding by facilitating the building and maintenance of parental, sexual, and sameâsex social relationships. However, we do not know whether the function of the avian homologue mesotocin is evolutionarily conserved across birds. While it does influence avian prosocial behavior, mesotocin\u27s role in avian social bonding remains unclear. Here, we investigated whether mesotocin regulates the formation and maintenance of sameâsex social bonding in pinyon jays (Gymnorhinus cyanocephalus), a member of the crow family. We formed squads of four individually housed birds. In the first, âpairâformationâ phase of the experiment, we repeatedly placed pairs of birds from within the squad together in a cage for short periods of time. Prior to entering the cage, we intranasally administered one of three hormone solutions to both members of the pair: mesotocin, oxytocin antagonist, or saline. Pairs received repeated sessions with administration of the same hormone. In the second, âpairâmaintenanceâ phase of the experiment, all four members of the squad were placed together in a large cage, and no hormones were administered. For both phases, we measured the physical proximity between pairs as our proxy for social bonding. We found that, compared with saline, administering mesotocin or oxytocin antagonist did not result in different proximities in either the pairâformation or pairâmaintenance phase of the experiment. Therefore, at the dosages and time frames used here, exogenously introduced mesotocin did not influence sameâsex social bond formation or maintenance. Like oxytocin in mammals, mesotocin regulates avian prosocial behavior; however, unlike oxytocin, we do not have evidence that mesotocin regulates social bonds in birds
Linking benthic biodiversity to the functioning of coastal ecosystems subjected to river runoff (NW Mediterranean)
Continental particulate organic matter (POM) plays a major role in the functioning of coastal marine ecosystems as a disturbance as well as an input of nutrients. Relationships linking continental inputs from the Rhone River to biodiversity of the coastal benthic ecosystem and fishery production were investigated in the Golfe du Lion (NW Mediterranean Sea). Macrobenthic community diversity decreased when continenÂŹtal inputs of organic matter increased, whereas ecosystem production, measured by common sole (Solea solea) fishery yields in the area, increased. Decreases in macrobenthic diversity were mainly related to an increasing abundance of species with specific functional traits, particularly deposit-feeding polychaetes. The decrease in macrobenthic diversity did not result in a decrease, but an increase in ecosystem production, as it enhanced the transfer of continental POM into marine food webs. The present study showed that it is necessary to consider functional traits of species, direct and indirect links between species, and feedback loops to understand the effects of biodiversity on ecosystem functioning and productivity
The Bismut-Elworthy-Li type formulae for stochastic differential equations with jumps
Consider jump-type stochastic differential equations with the drift,
diffusion and jump terms. Logarithmic derivatives of densities for the solution
process are studied, and the Bismut-Elworthy-Li type formulae can be obtained
under the uniformly elliptic condition on the coefficients of the diffusion and
jump terms. Our approach is based upon the Kolmogorov backward equation by
making full use of the Markovian property of the process.Comment: 29 pages, to appear in Journal of Theoretical Probabilit
Hypoglycaemia events with iGlarLixi versus premix biphasic insulin aspart 30 (BIAsp 30) in people with type 2 diabetes advancing from basal insulin:An analysis of the SoliMix trial
Aims To explore details of the incidence and rates of daytime and nocturnal hypoglycaemia, levels of hypoglycaemia, and relationship to glycated haemoglobin (HbA1c), when comparing iGlarLixi versus premixed biphasic insulin aspart 30 (BIAsp 30) in the SoliMix randomized controlled trial. Materials and Methods This exploratory analysis of SoliMix used logistic regression and negative binomial regression analyses to assess between-treatment differences in the incidence and rates of hypoglycaemia by time of day. A negative binomial model was used to derive estimated annualized hypoglycaemia rates as a function of HbA1c. Results iGlarLixi was associated with lower incidence and rates of American Diabetes Association Level 2 (<54 mg/dL [<3.0 mmol/L]) hypoglycaemia during both night and day versus BIAsp 30. Incidence and rates of Level 1 (<70 to >= 54 mg/dL [<3.9 to >= 3.0 mmol/L]) hypoglycaemia were also mostly shown to be reduced with iGlarLixi versus BIAsp 30. Severe (Level 3) events were too few for analysis (n = 3). iGlarLixi was associated with lower modelled event rates of Level 2 and Level 1 hypoglycaemia over a wide range of HbA1c levels versus BIAsp 30. Conclusions These results show that the lower HbA1c levels and weight benefit seen with iGlarLixi versus premixed BIAsp 30 in people with type 2 diabetes advancing their basal insulin therapy in the SoliMix trial are also accompanied by a lower risk of hypoglycaemia at any time of day and across a broad range of HbA1c levels
A study of the static yield stress in a binary Lennard-Jones glass
The stress-strain relations and the yield behavior of model glass (a 80:20
binary Lennard-Jones mixture) is studied by means of MD simulations. First, a
thorough analysis of the static yield stress is presented via simulations under
imposed stress. Furthermore, using steady shear simulations, the effect of
physical aging, shear rate and temperature on the stress-strain relation is
investigated. In particular, we find that the stress at the yield point (the
``peak''-value of the stress-strain curve) exhibits a logarithmic dependence
both on the imposed shear rate and on the ``age'' of the system in qualitative
agreement with experiments on amorphous polymers and on metallic glasses. In
addition to the very observation of the yield stress which is an important
feature seen in experiments on complex systems like pastes, dense colloidal
suspensions and foams, further links between our model and soft glassy
materials are found. An example are hysteresis loops in the system response to
a varying imposed stress. Finally, we measure the static yield stress for our
model and study its dependence on temperature. We find that for temperatures
far below the mode coupling critical temperature of the model (),
\sigmay decreases slowly upon heating followed by a stronger decrease as
\Tc is approached. We discuss the reliability of results on the static yield
stress and give a criterion for its validity in terms of the time scales
relevant to the problem.Comment: 14 pages, 18 figure
Pest management and biodiversity in organic fruit production: the case of apple orchards
Numerous pesticide applications are required for orchard protection, regardless of the guidelines. Organic fruit production (OFP) mainly relies on the use of mineral fungicides and microbiological or naturally-occurring insecticides. The environmental impact of this type of production does not significantly differ from that of conventional production when assessed in terms of synthetic indicators. However, the abundance of earthworms, as well as the abundance and specific richness of arthropod pests and beneficials in the orchards and surrounding hedges, is greater in OFP than in conventional orchards. Generalist predators are usually less affected by OFP compounds than by the chemical pesticides applied in conventional orchards. OFP also benefits avian communities, and above all, insectivorous birds, for which organic orchards offer a suitable habitat similar to that of undisturbed natural areas. In addition to this general trend, discrepancies may be observed in the protection responses of different insect groups. The abundance of hymenopteran parasitoids is the lowest in organic orchards in which outbreaks of phytophagous mites are also recorded in relation to the intensive use of sulphur for scab protection. Biological insecticides often act in ways that are similar to those of chemical ones, and the restricted choice of available compounds is likely to induce resistance selection in insect pests. Although maintaining biodiversity is not a direct result of the implementation of OFP guidelines, it seems to be widely considered as an option by organic growers, both alone and as a complementary tool for pest regulation
Quantum Impurities and the Neutron Resonance Peak in : Ni versus Zn
The influence of magnetic (S=1) and nonmagnetic (S=0) impurities on the spin
dynamics of an optimally doped high temperature superconductor is compared in
two samples with almost identical superconducting transition temperatures:
YBa(CuNi)O (T=80 K) and
YBa(CuZn)O (T=78 K). In the Ni-substituted
system, the magnetic resonance peak (which is observed at E40 meV in
the pure system) shifts to lower energy with a preserved E/T ratio
while the shift is much smaller upon Zn substitution. By contrast Zn, but not
Ni, restores significant spin fluctuations around 40 meV in the normal state.
These observations are discussed in the light of models proposed for the
magnetic resonance peak.Comment: 3 figures, submitted to PR
A Retinoic Acid Responsive Hoxa3 Transgene Expressed in Embryonic Pharyngeal Endoderm, Cardiac Neural Crest and a Subdomain of the Second Heart Field
A transgenic mouse line harbouring a ÎČ-galacdosidase reporter gene controlled by the proximal 2 kb promoter of Hoxa3 was previously generated to investigate the regulatory cues governing Hoxa3 expression in the mouse. Examination of transgenic embryos from embryonic day (E) 8.0 to E15.5 revealed regionally restricted reporter activity in the developing heart. Indeed, transgene expression specifically delineated cells from three distinct lineages: a subpopulation of the second heart field contributing to outflow tract myocardium, the cardiac neural crest cells and the pharyngeal endoderm. Manipulation of the Retinoic Acid (RA) signaling pathway showed that RA is required for correct expression of the transgene. Therefore, this transgenic line may serve as a cardiosensor line of particular interest for further analysis of outflow tract development
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